Re: Problem Using a Commodore 1084s Monitor on a IIgs

[Polymorph <polymorph69@hotmail.com>]

On Feb 12, 11:03 am, Alex Freed <al...@mirrow.com> wrote:
> Polymorph wrote:
>
> > I'm not sure, but those sites seem to suggest that the input should be
> > 0.7 P-P. What does P-P stand for? I assume 0.7 is the voltage level?
>
> Indeed it is 0.7 volts. P-P stands for "peak to peak" as opposed to say RMS.
>
>
>
> > As there are so many people successfully using 1084 monitors on a IIgs,
> > and nobody has mentioned the need for an inverter, I would guess that
> > this is not the case - but I could be wrong.
>
> I am one. No inverters needed, but the Amiga monitor I have appears to
> have a strong internal pull-up. It's not the voltage that is a problem,
> but rather the fact that it never gets low enough. My solution was a
> 51 ohm resistor to the ground. Works like a charm
>
> -Alex.

Alex,

I'm just curious how you arrived at 51 Ohms. Was it through trial and
error, or some other means of deduction?

When you wired up the 51 Ohm resistor, I assume it was in the same
manner as I tried with a 75 Ohm resistor - i.e. the resistor between
the composite sync and ground?

Could you do me a favour and measure what the voltage is between
composite sync and ground? It could be that I haven't lowered my
composite sync signal quite enough? Maybe the sync level is 0.3V P-P.
I think this is what is listed for one of the other 1084 inputs.
Perhaps this is an omission from the specs of the RGB port?

Thanks for the help!

Cheers,
Mike